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Smarty UnlimitedUnltddataUnltdminutesUnltdtexts1month contractZeroupfront cost£15.00per monthGet DealSmarty
5G SIM Only UnlimitedFree EU RoamingFree Roaming up to 30GBUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£16.00per monthGet DealiD Mobile
5G SIM Only UnlimitedFree EU RoamingFree Roaming up to 30GBUnltddataUnltdminutesUnltdtexts1month contractZeroupfront cost£16.00per monthGet DealiD Mobile
5G SIM Only UnlimitedFree EU RoamingFree Roaming up to 30GBUnltddataUnltdminutesUnltdtexts12month contractZeroupfront cost£17.00per monthGet DealiD Mobile
5G SIM Only UnlimitedFree EU RoamingFree Roaming up to 30GBUnltddataUnltdminutesUnltdtexts1month contractZeroupfront cost£18.00per monthGet DealiD Mobile
Lite SIM Only UNLIMITEDUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£20.00per month(prices may change during contract)Get DealThree
Lite SIM Only UNLIMITEDUnltddataUnltdminutesUnltdtexts12month contractZeroupfront cost£21.00per month(prices may change during contract)Get DealThree
SIM OnlyUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£25.00per month(prices may change during contract)Get DealO2
SIM Only UnlimitedFree EU RoamingUnltddataUnltdminutesUnltdtexts18month contractZeroupfront cost£25.00per month(prices may change during contract)Get Dealgiffgaff
Value SIM Only UnlimitedUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£25.00per month(prices may change during contract)Get DealThree
Lite SIM Only UNLIMITEDUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£26.00per month(prices may change during contract)Get DealThree
Value SIM Only UnlimitedUnltddataUnltdminutesUnltdtexts12month contractZeroupfront cost£26.00per month(prices may change during contract)Get DealThree
Lite SIM Only UNLIMITEDUnltddataUnltdminutesUnltdtexts12month contractZeroupfront cost£28.00per month(prices may change during contract)Get DealThree
Unlimited SIM OnlyUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£30.00per month(prices may change during contract)Get DealVodafone
Complete SIM Only UNLIMITEDUnltddataUnltdminutesUnltdtexts24month contractZeroupfront cost£30.00per month(prices may change during contract)Get DealThree
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Cable.co.uk may earn a commission when you purchase via links on our site. The price you pay will always be equal to or often cheaper than the price you would pay by going direct to the provider. Please refer to individual provider's terms and conditions before signing up. All prices are inclusive of VAT except business prices.

Why choose a SIM with unlimited data?

Here's the thing. Most of us spend most of our time within range of a wifi signal. In fact, I think many would be shocked just how little mobile data they use, especially those of us that regularly connect to wifi at home, work and at the houses of friends and family. According to Ofcom's most recent report, the average UK mobile user uses just 8GB of mobile date per month. 8GB! Puts it in perspective, doesn't it.

However, there are those who either have a job where they are out and about more than at home, or others with time to fill on a long commute. So, here are four reasons you might want to pick an unlimited data mobile SIM over any other type.

5G uses up data faster

If you can download data more quickly then you may download larger files because of the shorter wait times, and so you may also find yourself downloading more. For example you might choose the 4k version of a movie instead of the 1080p one. In addition, some streaming services may simply pipe the heftier 4K version to you automatically because it has detected you have the bandwidth available. So it is quite likely that having a 5G connection will cause you to eat data more quickly, by default, as it were, which in turn makes an unlimited connection much more attractive.

You stream a lot

If you watch a lot of streamed video content on YouTube, Netflix or other, and you tend to do that while you're out and about, then there is potentially a need for either a very large data limit, or more ideally, an unlimited data SIM-only plan.

You download a lot of apps and games

Equally, apps and games can be pretty huge these days, so if you're a keen mobile gamer and like to try a lot of different apps and games each month, there's potentially an argument to choose an unlimited data SIM deal over any other type of plan.

You just don't want to think about data

This one covers the people with jobs or commutes where they would like to use a lot of data on the move. But it is also the reason most of us here at Cable.co.uk have unlimited data SIMs in our phones: it's no longer that expensive and you can just forget about data limits altogether. At the time of writing, we've seen unlimited data SIMs for as little as £16 per month, and there are a lot of limited SIMs out there that cost more than that. Unlimited data is set to become the rule rather than the exception.

Why you don't need an unlimited SIM

We know you're here for an unlimited SIM, and we're happy to help you choose one. However, our goal is to provide the best consumer advice we possibly can, and it would be remiss of us to let you go and pick up a SIM with unlimited data if you dont really need one. They cost more (broadly), and most people simply don't need unlimited data yet in 2024. Phones and our consumption needs, along with how long we tend to spend away from our wifi connections don't generally add up to needing unlimited data.

In fact, with an average monthly usage of just 8GB here in the UK, it could be argued that picking a SIM with a low limit is more sensible for most people. That's for the most par true, but it's never going to be a case of one size fits all. We do have different data needs, depending on both how often we lean on our data allowance away from wifi, and the sorts of things we tend to do with our phones when we're out and about.

Here are the most common uses for our mobile phones and how much data they use on average:

Activity (while not on wifi) Average data used
Email 20KB
Email (with attachment) 300KB
Downloading a song 4MB
Browsing the web 15MB per hour
Browsing Instagram 100MB per hour
Browsing Facebook 156MB per hour
Browsing X (formerly Twitter) 360MB per hour
Streaming standard-definition (SD) video 700MB per hour
Streaming high-definition (HD) video 2.5GB per hour
Streaming ultra-HD (4K) video 5.8GB per hour
Streaming music 72MB per hour
Online gaming 80MB per hour

Take some time to calculate what you actually need. If it turns out it's hundreds of gigabytes then fair enough – unlimited it is. But if it's not, you could be saving money. The other way to check how much data you need is to check your existing usage, which will be stored in your phones info in its settings menu. Again, we're willing to bet that nine times out of ten, unlimited is also unnecessary.

Which providers offer unlimited SIM deals?

Almost all of them do at this point. Unlimited SIMs were a relative rarity up until just a couple of years ago, but now they are ubiquitous – they're everywhere. However, not all providers offer the same thing, despite the SIMs functioning largely the same. Providers tend to have a focus that differentiates them from competing providers.

For example, VOXI focuses on low prices and no frills, Three on its rewards programme and generous roaming terms, EE on its download speeds and coverage, Vodafone on its bolt-on features and flexibility. It's a good idea to know what additional features are available and who tends to focus on those features.

To assist in making that choice, here's a quick overview of what providers tend to focus on what. There's some crossover here, and don't expect any particular focus to be a sole focus. Broadly, all providers offer the same basics:

  • Asda Mobile – ASDA speciality is pay as you go 30-day bundles. You top up your account and then use that credit to buy a bundle of data, texts and minutes, you can also turn it into a recurring bundle. ASDA Mobile uses the EE network
  • iD Mobile – iD mobile's focus is on low pricing without decimating features like roaming and tethering. It uses the Three network to deliver its services
  • giffgaff – giffgaff’s SIM plans are called Goodybags and all last 30 days, though it has recently introduced a contracts plan called the 'Good Contract'. The provider, which runs on the O2 network, also offers unlocked mobile phones
  • SMARTY – SMARTY, which uses the Three network, only offers one-month plans and they all offer a discount at the end of the month for any data you haven’t used. SMARTY's speciality is being cheaper than anyone else, and it largely succeeds in that
  • Tesco Mobile – Tesco Mobile, which runs on the O2 network, has a range of unlimited SIM deals and specialises in low pricing, flexibility and generous family plans (where you take out multiple SIMs for other household members)
  • Plusnet mobile – Plusnet, best known for its broadband deals and award-winning customer service, also offer mobile SIMs at cheap prices. It's also the only provider in this list that doesn't offer unlimited SIMs. Still a good choice though, if you've decided an unlimited SIM isn't required
  • EE – Specialises in ubiquitous coverage and fast 5G speeds, usually winning speed contests year on year
  • Vodafone – Vodafone offers cheap base SIMs while allowing customers to bolt on all the extra bits as and when they need them. This modular system isn't unique, but no one does it quite as well as Vodafone
  • Three – Three has a handful of mostly big-data and unlimited data SIM deals. It adds additional value through its Three Rewards programme and its excellent app
  • O2 – The provider specialises in fast data, and now it's a part of Virgin Media you can also now bundle in an O2 SIM for a very small monthly fee with your Virgin Media Broadband and TV bundle

Are unlimited SIMs truly unlimited?

It may seem obvious, but like an all-you-can-eat buffet there are still rules. You can't turn up at the counter with a wheelie bin and clean them out, and likewise, with unlimited SIMs there are some rules that apply in some instances that mean, in reality, your data won't be totally unlimited. They are:

Roaming is never, ever unlimited

Different providers have different roaming rules, but one thing you can be sure of is that none of them offer unlimited usage when abroad, even when you're in one of the countries they list as offering free roaming. Limits tend to fall between about 10GB and 50GB depending on the provider, so it's a good idea to know your own limit before heading off abroad. Just for the same of example, here are the roaming limits for the four major network providers (O2, Three, Vodafone and EE):

Provider Additional cost Data limit
EE £2.29 per day on contract, £2.50 per day for PAYG 50GB
O2 None 25GB
Three £2 per day for contracts, PAYG remains pay as you go in the EU at no extra cost. A data passport is available for £5 for unlimited data to 89 additional countries 12GB
Vodafone £2.25 per day for contracts, £7 for 8 days for PAYG 25GB

Tethering is sometimes unlimited

Tethering – using your phone as a wifi hotspot to connect other devices to and share its internet connection – is stated as unlimited by just about every provider, but guess what? It often isn't. Some providers have 6-month limits on tethering they hide in their FUP (fair usage policy). If tethering matters to you, and you do it a lot, you may wish to take the following into consideration:

Network Overall tethering allowance Maximum tethering data per 6 months
Three Unlimited No limit
EE Unlimited 600GB
O2 Unlimited 650GB
Vodafone Unlimited No limit
VOXI Unlimited No limit
Giffgaff Unlimited 650GB
iD Mobile Unlimited No limit
Smarty Unlimited No limit
Asda Mobile Unlimited No limit
Lebara Mobile Unlimited No limit
Tesco Mobile Unlimited No limit
Lyca Mobile Unlimited 450GB
Talkmobile Unlimited No limit

Frequently asked questions

What is an unlimited SIM?

An unlimited SIM provides limitless data for a fixed monthly fee, allowing you to use your mobile phone without worrying about exceeding allowances.

How does unlimited data work?

Unlimited data means you can use as much mobile data as you need without any restrictions. It's ideal for heavy data users who stream videos, download large files, or browse the internet extensively.

Are there any limitations with unlimited SIMs?

While unlimited SIMs offer unrestricted data usage, some providers may have fair usage policies (FUPs) that apply. These policies may limit data speeds or usage in certain circumstances, such as excessive tethering.

Can I use an unlimited SIM for tethering?

Yes, all unlimited SIMs allow tethering, enabling you to share your mobile data connection with other devices such as laptops or tablets. However, be sure to check your provider's terms and conditions regarding tethering as sometimes there are hidden limits.

Are there any hidden charges with unlimited SIMs?

While unlimited SIMs offer comprehensive packages, it's essential to review the contract terms for any hidden charges or additional fees. These may include charges for exceeding fair usage policies, international usage, picture texts, or for premium services.

How do I choose the right unlimited SIM deal?

To choose the best unlimited SIM deal, assess your data, call, and text requirements, compare providers for coverage and network quality, and consider any additional features or perks offered by each deal.

Can I keep my existing mobile number when switching to an unlimited SIM?

Yes, you can usually keep your existing mobile number when switching to an unlimited SIM. This process is known as porting and can be arranged with your new provider during the sign-up process.

Do I need to sign a contract for an unlimited SIM?

Many unlimited SIM deals require a contract commitment, typically ranging from 12 to 24 months. However, some providers offer pay-as-you-go options or shorter contract lengths for greater flexibility.

What happens if I exceed my data allowance on an unlimited SIM?

With an unlimited SIM, there is no data allowance to exceed. However, if your provider has a fair usage policy in place, excessive data usage may result in reduced speeds or additional charges, so it's essential to review the terms of your contract.

Can I use an unlimited SIM abroad?

Using an unlimited SIM abroad depends on your provider's international roaming policies. While some providers offer inclusive roaming in certain destinations, others may charge additional fees for using data, calls, or texts outside the UK. Check with your provider for specific details.